A simple and chemically intuitive approach is used to design ptC-containing E-C clusters (E = Si-Pb). This approach consists in replacing three or two consecutive protons from an aromatic hydrocarbon by one E 2 4+ or one E 2+ fragment, respectively. In the model, electrons from E are removed from the p z orbitals, emptying them. Si-Pb favors the formation of a 3c-2e (E-C-E) σ-bond, which involves the ptC. Additionally, the π-electronic cloud is delocalized through the E-p z orbitals allowing the E atoms to effectively take part in the electronic delocalization, preserving the 4n + 2 Hückel's rule from the parent hydrocarbon. Two aromatic monocycles and one aromatic bicycle-benzene (C 6 H 6 ), cyclopentadienyl anion (C 5 H 5 - ) and pentalene dianion (C 8 H 6 2- )-have been transformed into C-E systems. After an extensive exploration of their potential energy surfaces, four new global minima with ptC are identified, resulting from the substitution of the protons by Si and Ge cations in C 5 H 5 - and C 8 H 6 2- (E 3 C 5 and E 4 C 8 ). The analysis of both the chemical bonding and the magnetic response to an external magnetic field confirms the aromatic character of these species.
ASJC Scopus subject areas
- Materials Chemistry